Strategies aimed at limiting and repairing the damage attributed to oxidative stress may slow the advance of numerous age-related diseases. Numerous studies indicate that the enzyme cyclooxygenase-2 (COX-2) is induced by oxidative stress, contributes to oxidative stress, and promotes subsequent neuronal injury. In this application we propose continuation of our studies carried out under a Phase I SBIR grant to identify suitable COX-2 inhibitor new chemical entities (NCEs) to address oxidative stress-induced damage to the neuronal cells. The overall aim of the proposed grant application is to advance our initial discovery of a novel activity toward a clinical application of these NCEs. During the Phase I grant period, we established that certain Onconova COX-2 inhibitors (analogs of the ON 09 and ON 26 series), but not other commercially available COXibs, prevented oxidative stress-induced programmed neuronal cell death in vitro. Additionally, we demonstrated that systemic administration of naproxen, a non-selective COX inhibitor, partially but potently prevented the injury induced by direct intrahippocampal injection of the glutamate agonist, N-methyl- D-Aspartate (NMDA). Thus, the objectives of this Phase II research plan of study are as follows: 1) to determine the therapeutic potential of a novel COX-2 compound (ON 26040) against oxidative stress-induced neuronal injury in vivo. Studies will be undertaken to identify whether ON 26040 can effectively prevent injury induced by a) direct hippocampal injection of NMDA and/or b) striatal injury associated with systemic injection of 3-nitroproprionic acid; 2) To identify the molecular mechanism mediating the neuroprotective effects of ON 26040 in vitro. Studies will utilize the HCA injury model to analyze COX-dependent and/or -independent mechanisms of death suppression. Specifically, the ability of ON 26040 to modulate the Akt/PKB and extracellular signal-regulated kinase (ERK) signal transduction pathways will be explored; 3) to develop a pre-clinical safety and pharmacology profile of ON 26040 for regulatory submission. Studies will involve short term (7 day) and long term (28 day) repeat dose toxicology studies in rats and dogs and complete pharmacological assessment in both in vitro and in vivo models (rodents and canines). Specifically, this complete pre-clinical evaluation package will permit filing of an Investigational New Drug (ND) application for human clinical studies; and 4) To develop a clinical Phase I protocol for testing the safety of ON 26040 in human volunteers. This will involve selection of appropriate clinical therapeutic indication based on animal models and the establishment of dosing, testing and monitoring guidelines for an FDA and IRB approved study to be conducted following the completion of studies proposed herein.